I was 2/3 of the way in backing up 250 GB to OneDrive. Previously, I had restarted the computer and the backup picked up where it had left off. This time, it spent a while “Verifying back end data” and restarted backup from zero!
Logs might help if you have any. First though, is this OneDrive for Business? That’s not the same as OneDrive, and there’s a limit on the number of files that can be seen in one folder. Your backup size is pushing very close.
Any Warning or Error details on page, or in job log (Reporting --> Show log --> General) or in the server log at MENU --> About --> Show log --> Stored (look for logs that have roughly the right date and time for the backup, however if the backup is still running, you might not have a log yet). Just trying to gather some clues about this.
How long did it take to get 2/3 of the way through 250 GB? If that’s what it takes to get this, debug may be slow.
Log says (for today) "Failed while executing “Backup” with id:1. This is because I was using the laptop without Internet connection. This error is expected.
It had taken about 3 days to get up to about 180 GB (of a total of about 250GB).
As an update, this “new backup from zero”, advanced relatively quickly. About three hours through the 180GB. My guess is that it was skipping the files already uploaded to OneDrive. It then slowed down and seems to be uploading again.